In this study sample, a 10 μg/m3 reduction in the home outdoor PM10 concentration over a 10-year period reduced the annual rate of decline on average by 4 ml (95% CI 1 to 8) for
FEV1, 1 ml (−4 to 5) for FVC, 144 ml (6 to 22) for FEF25–75, and 7 ∗ 10−4 (1 ∗ 10−4 to 1.3 ∗ 10−3) for FEV1/FVC.